Uniform gas and coolant distribution may improve the performance of Proton Exchange Membrane (PEM) fuel cell systems while reducing balance of plant requirements. As the number of cells in a stack increases, however, creating uniform gas flow conditions throughout the stack may become difficult. Gas flow variation in a 400 cell fuel cell stack, for example, may cause lower gas velocities in some cells and higher gas velocities in other cells. The reduced flow in some cells may result in lower current densities or cell flooding. Similarly, excessive flow can also lead to durability concerns within the fuel cell stack.